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Courtesy of Janice Haney Carr/CDC/ Paula Smith

Doodlebug

Under a relatively-low magnification of 155X, twice that of PHIL 11804, this scanning electron micrograph (SEM) revealed the ultrastructural features found on the ventral exoskeletal surface of this larval-staged antlion’s mandibles. This larva is sometimes referred to as a “doodlebug”, because of the trails it leaves in the soft sand as it hunts for prey. This arthropod, i.e., jointed legs, undergoes dramatic morphologic changes when it metamorphoses into a beautiful flying antlion lacewing.

These large mandibles are used to apprehend prey that unwittingly fall into the conical sand trap constructed by this carnivore. You’ll note the presence of numerous “hairs” covering virtually the entire exoskeletal surface. Referred to as setae, these are not the hairs that are common to mammals, but are composed of chitin, as is the exoskeleton itself, and are sensorial in nature, providing the insect larva with environmental data, including temperature, tactile stimuli, and chemical changes. Note the particulates dispersed over the exoskeletal surface representing environmental debris.